This invention relates to the storage of thermal energy, in particular but not exclusively the storage of energy received from solar heating.
The increasing interest in the use of solar energy in recent years had indicated the need for means to store thermal energy for periods of at least several hours, and preferably for considerably longer periods. Methods proposed so far include the storage of energy in hot water, in particular for domestic use, or in refractories or phase-changing salts. These methods all have their limitations. The maximum temperature that can be realised with heat energy storage in water or in phase-changing salts is very restricted, while the storage process in refractories is slow due to the bulk of the material. All the methods in fact require bulky and therefore expensive installations.